Pipeline scraper-passing method and system



Feb. 18, 1969 J. w. GENTRY, JR

PIPELINE SCRAPER-PASSING METHOD AND SYSTEM Original Fild May 1. 1963Sheet fit Feb. 18, 1969 J. w. GENTRY, JR

PIPELINE SCRAPER-PASSING METHOD AND SYSTEM Sheet Original Filed May 1.1963 Feb. 18, 1969 J. w. GENTRY, JR I 3,428,489

PIPELINE SCRAPER-PASSING METHOD AND SYSTEM Original Filed May 1'. 1963Sheet 3 of3 United States Patent 3,428,489 PIPELINE SCRAPER-PASSINGMETHOD AND SYSTEM John W. Gentry, Jr., Dobbs Ferry, N.Y., assignor toThe Texas Pipe Line Company, Houston, Tex., a corporation of TexasOriginal application May 1, 1963, Ser. No. 277,245. Divided and thisapplication Oct. 12, 1964, Ser. No. 411,957 US. Cl. 134-8 1 Claim Int.Cl. B08b 9/04 ABSTRACT OF THE DISCLOSURE A method of pipeline pumping.The approach of a scraper to a pumping station triggers a by-passingconnection that sends the scraped debris and scraper around a loopwithout going through the pump.

This is a division of application Ser. No. 277,245, now Patent No.3,212,116.

This invention concerns a method and system for a pipe line operation.More specifically, the invention concerns an operation related to thepassing of a scraper through a pipe line past a pumping station, withoutsubjecting the pumping station to debris that has been scraped free inconjunction with the scraper passing along in the pipe line.

Prior to this invention there have been arrangements for receiving ascraper at a pumping station and then reinserting same for continuingpassage down the pipe line. However, such arrangements necessitated themanual removal of the scraper and reinsertion thereof for continuing thescraping operation on downstream. Consequently, there was no automaticprovision for receiving and passing along a scraper at an unattendedpumping of booster station. Furthermore, even if some arrangement hadbeen made whereby the scraper could be bypassed around the pump of abooster station, this would not have avoided having the debris that hadbuilt up ahead of the scraper from being carried through the pump withconsequent extra Wear and damage to the mechanical seals by reason ofthe nature of such dirt, sand, welding splatter, paraflin and otherdebris.

Consequently, it is an object of this invention to teach a method of pasing a scraper without subjecting the pumping station (being passed bythe scraper) to have any of the debris, or the scraper itself, passthrough the pump at the station.

Another object of the invention is to provide a system that isparticularly adapted for use with an unattended pumping station, andthat provides for the passing of a scraper along with all accumulateddebris without any of the debris or the scraper going through the pumpitself.

Another object of the invention is to provide a pumping station with aloop structure connected to the pipe line. The arrangement being suchthat the arrival of a scraper may be detected at the upstream end of theloop, and the pipe line connections to the pumping station may then beswitched from the downstream end of the loop to the upstream end, abovethe scraper. In this manner the scraper and accumulated debris isallowed to pass through the loop and on down the line. Then, upondetection of the scraper at the downstream end of the loop, the pumpingstation connections may be switched back to the downstream end to awaitarrival of the next scraper.

Briefly, the invention may be described as one applicable to pipe lineoperations involving a pumping station. The invention comprises a methodof passing a scraper without subjecting the pumping station to scraperaccumulated debris. Such method includes the steps of sens- "ice ing thearrival of said scraper upstream from said station at a distance greatenough to prevent any debris from entering the station, and switchingthe inlet for said station to a location upstream from said scraper. Themethod also comprises the steps of switching the outlet for said stationto a location upstream from said scraper, sensing the passage of saidscraper downstream from the original location of the outlet before saidfirst named sensing of the scraper, and switching the inlet and outletfrom said station back to the original locations to be ready to passanother scraper.

Again briefly, the invention is applicable to an automatic pumpingstation of a pipe line which has means for passing a scraper withoutflowing any scraper debris through the pump. The invention comprises apipe line having a loop adjacent to said station, an inlet line to saidstation and an outlet line from said station. It also comprises a firstpair of motor driven valves having one side connected to branches ofsaid inlet line, and a second pair of motor driven valves having oneside connected to branches of said outlet line. The other side of saidpairs of valves are connected respectively to said pipe line near theupstream and downstream ends of said loop. The invention also comprisesa first signal indicator located near the upstream end of said loop insaid pipe line for indicating passage of a scraper, and a second signalindicator located near the downstream end of said loop for detectingpassage of the scraper. The invention also comprises control meansactuated by said indicators for causing one of each of said first andsecond pair of valves to open and the other of each pair to close inorder to shift said inlet and outlet lines from a downstream locationrelative to said scraper to an upstream location relative thereto.

The foregoing and other objects and benefits of the invention will bemore fully appreciated in connection with a particular embodiment thatis set forth by way of illustration, and that is illustrated in thedrawings where- FIGURE 1 is a schematic perspective view showing anautomatically operable pumping station as connected into a pipe line forcarrying out the invention;

FIGURE 2 is a schematic diagram of .the pipe line loop with connectionsto and from the pumping station, and including a schematic electricalcircuit diagram showing the basic circuits for actuating the controls ofthe valves in the system;

FIGURE 3 is a side elevation illustrating a typical motor operatedvalve, such as may be employed in the various switching control valvesof the system;

FIGURE 4 is a side elevation partly broken away in cross-section, withthe view taken transversely of the pipe line, showing a typical scrapersignal indicator device; and

FIGURE 5 is a longitudinal cross-section view illustrating a typicalcheck valve which may be used in the required locations of the pipe lineincluding separating the inlet and outlet connections to the line fromthe pumping station.

Referring to FIGURE 1, the elements of a pumping station and itsconnections into the pipe line along with the elements according to thisinvention, will be generally described. It is pointed out that in theparticular embodiment of the invention that is being described, there isillustrated an automatic booster station which requires no attendanceunless some emergency situation arises. Thus, there is a pipe line 11having an upstream end connected to station A (as indicated by thecaption) while the downstream end thereof is connected to continue ontoward a station B. Between the upstream and downstream portions of thepipe line 11, there is a loop 12 connected into the line and this willbe ordinarily the same size pipe as is that of the main pipe line 11.Near the upstream end of loop 12 there are inlet and outlet connections15 and 16 respectively, which lead to respective motor controlled valves17 and 18. The valves 17 and 18 have the other side of each connected toa station inlet line 21 and a station outlet line 22 respectively.

Also connected to extensions of the station inlet and outlet lines 21and 22 respectively, there is another pair of motor controlled valves 25and 26. Valves 25 and 26 have connections from the other side of eachvia short inlet and outlet connections 29 and 30 respectively, to thedownstream end of the loop 12 of pipe line 11.

It will be observed that there is also some additional equipmentincluding a scraper signal indicator 33 (captioned Pig Signal No. 1)that is connected into the pipe line 11 near the upstream end of theloop 12. Similarly there is another scraper signal indicator 34(captioned Pig Signal No. 2) connected into the pipe line 11 near thedownstream end of the loop 12. Some auxiliary equipment that is employedin the system includes check valves 37 and 38 that are connected intothe pipe line between alternative inlet and outlet connections that leadto the pumping station. It is also usual to include a check valve 39 instation outlet line 22 and another check valve 40 in the station linebetween inlet and outlet to prevent any undesired back fiow or reverseaction during the operation of the pumping station.

It will be observed that the pumping station has the station inlet andoutlet lines 21 and 22 leading thereto from the alternative connectionsat either end of the loop 12. Of course the pumping station elementsform no part per se of the invention, but included at the pumpingstation may be the usual equipment. This may include a plurality of heatexchange units 43 and a pumping drive unit 44. Drive unit 44, in turn,may include an engine 45 connected to a pump 46 via a speed-change drivecoupling 47, all as illustrated. In addition there will be a pair ofmotor operated valves 50 and 51 for controlling the connection of pump46 to the station inlet and outlet lines, in case of shut down or thelike. It will be observed that there may be additional pumping units(not shown, but indicated) connected into the station inlet and outletlines, as desired, in order to increase the pumping capacity of thestation.

Method Operation of a method according to the invention will bedescribed in general with reference to FIGURE 1; while a description ofthe details concerning a particular electrically controlled, automaticoperating system will be described with reference to the other figures,particularly FIGURE 2, of the drawings. Thus, a method according to theinvention relates to pipe line operations involving a pumping station,e.g. unit 44 of FIGURE 1, and provides for a method of passing a scraperwithout subjecting the station to scraper accumulated debris.

The method comprises, among others, the step of sensing the arrival of ascraper upstream from the station at a distance great enough to preventany debris from entering the inlet line to the pumping station. Thisfirst step is carried out by having connections made and valves adjustedso that normal pumping operations are carried out with the inlet 21 tostation 44 connected into the downstream end of the loop 12. This isaccomplished by having valve 25 open while the valve 17 is closed. Atthe same time (for normal pumping operations) the outlet from pumpingstation 44 via outlet line 22, also is connected to the downstream endof loop 12 by having valve 26 open while valve 18 is closed. Then whenthe scraper arrives along pipe line 11 from station A, and reaches thesignal indicator 33, the sensing step has been accomplished.

A next step is that of switching the inlet for the station to a locationupstream from the scraper. This is accomplished in the systemillustrated, by the arrangement such that when the scraper passes thesignal indicator 33,

it will provide a signal that will actuate valve 17 to be opened whileat the same time valve 25 will be closed.

Another step is to switch the outlet for the station to a locationupstream from said scraper. This is accomplished as a unitary operationwith the prev1ous step. Thus, the outlet valve 26 will be closed whilevalve 18 is opened. In this manner the arrival of the scraper pastsignal indicator 33 will have been sensed while an ade quate length ofthe loop 12 insures that none of the debris which precedes the scraperas it travels through the line, will have yet reached the inletconnection 29 that was then connected to the station inlet 21 -via thethen open valve 25.

It will be appreciated that by having indicator 33 at the upstream endof the loop 12, the sensing of scraper arrival will be at the desiredlocation upstream from the inlet connection. Furthermore, it will beclear that other arrangements of apparatus might be made for carryingout the steps so far described.

A next step (following the switch-over of inlet and outlet connectionsto and from the pumping station 44) is that of sensing the passage ofthe scraper at a location downstream from the original location of theoutlet connection from pumping station 44. This step is carried out byhaving the signal indicator 34 located near the downstream end of loop12 so that when the scraper passes, a signal indication is created.

A final step is that of switching the inlet and outlet from the stationback to the original locations thereof in the pipeline so as to be readyto pass another scraper. Specifically, this involves a control actionwhich is initiated by the signal from indicator 34. The action is suchthat the valves 17 and 18 will be closed while valves 25 and 26 will beopened, all so as to restore the pumping station connections to the pipeline 11 back to the original locations, i.e. near the downstream end ofthe loop 12.

It will be noted that during this operation the method has provided forthe switching of connections to and from a pumping station such that thescraper and a substantial length of pipe line ahead of the scraper hasbeen bypassed without allowing any of the debris filled or contaminatedfluid associated with the scraper, to flow through the pumping stationat all. It will be appreciated that this method might be carried out invarious ways including manual operation and consequently the specificapparatus illustrated is not the only such, with which the method can becarried out.

Automatic operation of the system provides a highly beneficialarrangement which avoids the necessity of having any personnel attendthe station at all. Such automatic operation will be best understoodwith reference to FIGURE 2, in addition to FIGURE 1.

It is to be observed that the FIGURE 2 illustration is a highlyschematic diagram, and the various elements involved in the operationsare all well known commercial items that are readily available. Thus, itwill be noted that each of the motor controlled valves, e.g. valves 17,18, 25 and 26, may be electrically operated valves such as a typicalvalve 55 illustrated in FIGURE 3. This valve may be one manufactured byW-K-M-Co., 'Houston, Tex. Furthermore, the control arrangement foroperating such valves includes various elements of auxiliary valveoperator equipment (not shown). Such elements provide for starting andstopping of the valve operating motors, such as an electric motor 56that is illustrated with valve 55 in FIGURE 3. These operators includestandard relay controlled solenoid type motor starters with variousrelays and timing control elements being involved. In this manner theoperation involving opening one valve and simultaneously closinganother, may be adjusted with some difference in time delays so that theopening of the first valve may commence a few seconds before the closingof the second valve in order to provide proper operation of the system.However, the nonillustrated details of operator elements are unnecessaryto an understanding of the system according to this invention.

Automatic operation The details of the automatic operation of the systemwill be made clear in connection with particular reference to FIGURE 2,where there is illustrated a schematic diagram of the pipe line 11 andloop 12 in addition to the station inlet connection 21 and stationoutlet connection 22. The electrical control system includes a pair ofpower supply terminals 61, for receiving a source of electrical power(not shown).

There is a pair of control circuits connected in parallel acrossterminals 61 that includes a first circuit controlled by the scrapersignal indicator 33. This first circuit includes a circuit connection 62that leads to a switch 63 which is operated mechanically by the scrapersignal indicator 33. This electrical circuit continues from the otherside of switch 63 via a connection 66 to a relay, or control operator67, that acts to energize the operating motor of the valve 26 to drivethe valve to its closed position. At the same time the circuit continuesfrom relay 67 via a circuit connection 68 to another relay, or controloperator 69, which is associated with the valve 25. Energization ofrelay 69 will act to cause the operating motor of valve 25 to run in theproper direction to close this valve. The circuit continues from relay69 via a connection 72 to another relay, or control operator 73, whichis associated with the valve 17. It will be noted that relay, oroperator 73 is one which controls actuation of the operating motor toopen valve 17. The circuit then continues from relay 73 via anothercircuit connection 74 to another open relay, or control operator 75 thatcontrols the energization of the operator motor at valve 18 so as toopen this valve. Finally, the first circuit is completed from relay 75via a circuit connection 76 that leads back to the other one ofterminals 6'1 to complete an electrical circuit for energizing therelays, or control operators, which were connected in series in thatcircuit.

It will be appreciated that the schematic circuit showing of FIGURE 2 isa simplified arrangement. And, as already indicated above, the variouscontroller elements that are employed with the actuation of the motorfor each of the motor-controlled valves, involves considerableadditional equipment and complexity that is unnecessary to thisdescription insofar as providing for the necessary understanding of theinvention is concerned. Thus, it will be understood that when thescraper passes signal indicator 33 it momentarily closes switch 63 andthis will energize the circuit including relays 67, 69, 73 and 75. Thenthese relays will in each case actuate a holding circuit to energize andmaintain the operation required to carry out a cycle of opening orclosing action of each valve. This simultaneous opening and closing ofvalves 17, 18 and 25, 26 respectively, is carried out in accordance withpredetermined timing arrangements for each valve. In other words, theoperation will include energization of the motor drives for all fourvalves so as to shift the position of valves 25 and 26 from open toclosed while at the same time shifting valves 17 and 18 from closed toopen. These changes are actually carried out with the delay settingsmade so that valve 17 will commence opening a short while before valve25 begins to close in order to provide for a continuing supply of pipeline fluid to the inlet of the pumping station. Similarly, after apredetermined time delay valve 18 will commence to open a short whilebefore valve 26 begins to close, in order to transfer the outletpressure from the pumping station from the downstream end of the loop tothe upstream end behind the scraper.

The second of the pair of parallel electrical circuits connected toterminals 61 is for returning the valves to their original positionsafter the scraper has passed out of the loop and downstream along thepipe line. Thus, there is a circuit connection 81 that leads from theupper terminal 61 (as viewed in FIGURE 2) to a switch 82 that iscontrolled by the scraper signal indicator 34. The

circuit continues over a connector 83 to an open relay, or controloperator 84 that acts to control valve 26 for opening same. The circuitthen continues from relay 84 over a circuit connector 85 to anotherrelay, or control operator 86 and then over a connector 87 to a relay,or control operator 88 that controls the closing operation of valve 17.Then the circuit continues over a connector 89 to a relay, or controloperator 90 that controls the closing of valve 18. Finally the circuitis completed via a connector 91 which leads back to the other (lower)terminal 61.

When the scraper passes signal indicator 34, it will cause momentaryclosing of switch 82 and the second circuit (just described) will beenergized so that relays 84, 86 and 88, 90 will be actuated. Theserelays will control operation of the associated valves 26, 2'5 and 17,18

respectively, to cause reverse action to take place so that y the valveswill be returned to the positions occupied before the scraper firstreached signal indicator 33. Here again the changes will be carried outwith delay settings. In this case the valve 26 will first commenceopening a short while before the valve 18 begins to close; and after apredetermined (but shorter than in the first valve changes describedabove) time delay, the valve 25 will commence to open a short whilebefore valve 17 begins to close.

FIGURE 4 illustrates a typical scraper signal indicator which issubstantially like one that is commercially available and ismanufactured by T. D. Williamson, Inc., of Tulsa, Okla. For the purposesof understanding the operation and relating same to the system of thisinvention, it will be sufficient to note the following, as indicated bythe struct-uer illustrated in FIGURE 4. There is a trigger element 96that extends into the pipe line 11 through a hole 97 in the pipe. Thetrigger 96 is supported on, and fixed firmly for rotation at all timeswith a shaft 98. Thus, the trigger 96 is bolted to the shaft 98 by twobolts 99, as illustrated. At one end of shaft 98 there is a cam 102which is securely attached to the shaft 98 for rotation thereby andtherewith. There is a cam follower 103 in spring biased contact with cam102. Follower 103 acts to control actuation of a microswitch (not shown)located in a unit 104. On the other end of shaft 98, there may be anindicator arm 105 that provides visual indication of the position oftrigger 96. At the same time there will be an electrical indicationprovided by the actuation of the microswitch in unit 104. Thearrangement is such that trigger 96 is biased into its downward position(like that illustrated in FIGURE 4) so that following the passage of ascraper the trigger will be automatically reset so as to be ready toindicate again when another scraper passes. Consequently, the actuationof the microswitch in unit 104 will be of a relatively short duration,but as already'indicated above, the valve control motor energizationcycles that are commenced by the closing of the microswitch, merely needto be initiated and they will complete the opening and closing cyclesirrespective of the position of the trigger and microswitch unit,following commencement thereof.

FIGURE 5 merely illustrates a typical check valve structure which willbe employed in the indicated locations in the system, and which is soconstructed as to allow passage of a scraper that takes up the fulldiameter of the pipe line through which the scraper is passing. Such atypical check valve 108 may be a commercial unit, e.g., one manufacturedby Tom Wheatly Co. of Houston, Tex.

Operation in general The operation of a typical system may be reviewedby following the action as a scraper arrives along pipe line 11.Reference may be had to FIGURES 1 and 2 primarily. Thus, when a scraper(not shown) arrives at the station is goes past the inlet connection 15,which is taken off at right angles to the line, and it passes on through7 the check valve 38. This check valve 38 will then be already at leastpartially open, depending upon the rate of flow of fluid in the line,because valves 17 and 18 are closed. If the check valve is not wideopen, the scraper will merely contact the flapper of the valve and pushit fully open as the scraper passes by (see FIGURE The scraper will thencontinue through the line and pass the signal indicator 33 which willtherefore provide an electrical and a mechanical signal (see FIGURE 4and explanation thereof). The electrical signal is that caused by switch63 which is actuated by the signal indicator 33. Closing of this switch63 provides a completion of the circuit that was described previously sothat the relays 67, 69, 73 and 75 will be actuated and thus thevalve-motor controls will be set in motion to close valves 25 and 26while at the same time valves 17 and 18 will be opened. It will beobserved that at the time this happens, the scraper still is located farenough upstream (the length of the loop 12) from the inlet connection tothe pumping station so that none of the debris (including wax) precedingthe scraper will be carried into the inlet to the pumping station.

As the foregoing action of closing and opening the indicated pairs ofmotor controlled valves takes place, the inlet and outlet connectionsvia station lines 21 and 22 will be switched over from the downstreamend of loop 12 in the pipe line (on either side of check valve 37) tothe corresponding inlet and outlet connections for lines 21 and 22 thatjoin the pipe line 11 at the upstream end of the loop 12 (on either sideof check valve 38). Consequently, when the changeover of valve positionshas been completed, the inlet line 21 will have been shifted from aconnection to the pipe line via inlet connector 29 to a connection tothe pipe line via inlet connector 15. Likewise, the outlet line 22 fromthe pumping station will have been shifted from outlet connector 30 tooutlet connector 16. In this manner, the fluid being drawn into and outfrom the pumping station will have been switched over from a locationwell downstream of the location of the scraper, as detected or sensed byindicator 33, to a location upstream thereof.

The scraper will continue through the pipe line loop 12 and travelthrough check valve 37 to pass the other signal indicator 34, whilecarrying the scraper loosened debris mostly ahead of the scraper. As thescraper passes indicator 34 there will be similar action as when itpassed the signal indicator 33. Thus, this time switch '82 of indicator34 will be closed momentarily (and a mechanical signal will be provided)so that a circuit will be completed to energize the relays 84 and 86 aswell as relays 88 and 90 which will all act to set in motion the openingand closing respectively of the pairs of valves 25-26 and 17-18. In thismanner it will be clear that the motor controlled valves will then bereturned to their original state such that valves 25 and 26 are openwhile valves 17 and 18 are closed. Consequently, this latter action willcause a switching back of the inlet and outlet connections (to thepumping station) from the upstream end of the loop 12 to the downstreamend thereof. Thus, they are returned to the same condition as was thecase prior to the arrival of the scraper adjacent to the pumpingstation.

It will be observed that by reason of use of a system according to thisinvention, the need for any personnel in attendance at the station inconnection with the receipt and passage of a scraper, may be eliminated,In arrangements employed heretofore a scraper had to be directed into aspecial scraper receiving line or element from which is was necessary tomanually transfer the scraper over to the downstream side of the linerelative to the pumping statiQIl outlet.

It will be appreciated that a system in accordance with this inventionmay be arranged for pneumatic control of the various elements and thebasic operation will remain unchanged. For example, the scraper signalindicator could provide a pilot valve actuation upon passage of ascraper, in place of the electrical microswitch action described above.Then, such pilot valve would provide a control signal for a pneumaticsystem that would be in general the same as the electrical controlsystem which has been described. Consequently, the invention isapplicable to a station where no electrical power is available since theindicated pneumatic control system might be provided, with the pneumaticpower being generated as an auxiliary from the engine that drives thepump at the pumping station.

It will be appreciated that whereas the FIGURE 1 showing indicates rightangle bends at the corners of the loop 12, these corners would, in fact,be sufliciently large radius curvature piping so as to allow freepassage of the scraper without any danger of sticking.

The operation of both check valves 37 and 38 as well as the additionalcheck valves 39 and 40 illustrated, will be clear from the foregoingexplanations as well as from the knowledge of anyone skilled in the art.Thus, it is necessary to have a check valve between the inlet and outletconnections of the pumping station where they join the pipe line so asto provide effective pumping of the fluid in the pipe line without mererecirculation thereof. Similarly the use of check valve 39 is to avoidany backflow for any reason, which would tend to cause a reverse loadingsituation at the pump 46.

While preferred embodiments of the invention have been described abovein considerable detail in accordance with the applicable statutes, thisis not to be taken as in any way limiting the invention, but merely asbeing descriptive thereof.

I claim:

1. In pipeline operations involving a pumping station, a method ofpassing a scraper without subjecting said station to scraper accumulateddebris, comprising the steps of (a) sensing the arrival of said scraperupstream from said station at a distance great enough to prevent anydebris from entering the station,

(b) switching the inlet for said station to a location upstream fromsaid scraper,

(c) switching the outlet for said station to a location upstream fromsaid scraper,

(d) sensing the passage of said scraper downstream from the originallocation of the outlet from the station before said first named sensingof the scraper, and

(e) switching the inlet and outlet from said station back to theoriginal locations to be ready to pass another scraper.

References Cited UNITED STATES PATENTS 2,905,125 12/1960 Osborne l372683,047,020 7/1962 Barrett 15--104.06 X 3,135,278 6/1964 Foord l5104.06 X

HARRY B. THORNTON, Primary Examiner.

ROBERT HALPER, Assistant Examiner.

US. Cl. X.R.

